POV-Ray : Newsgroups : povray.documentation.inbuilt : using a helix_1 as a coil or helical spring, what is the Parameter P1 exact= Server Time: 23 Oct 2019 02:33:17 GMT
  using a helix_1 as a coil or helical spring, what is the Parameter P1 exact= (Message 1 to 2 of 2)  
From: rossy
Subject: using a helix_1 as a coil or helical spring, what is the Parameter P1 exact=
Date: 7 Jan 2004 17:20:01
Message: <web.3ffc3ea4b75066f8a840cd570@news.povray.org>
Hallo

it follows a cut out of the User Manual:
f_helix1(x,y,z, P0, P1, P2, P3, P4, P5, P6)

P0 : Number of helixes - e.g. 2 for a double helix
P1 : Period - is related to the number of turns per unit length
P2 : Minor radius (major radius > minor radius)
P3 : Major radius
P4 : Shape parameter. If this is greater than 1 then the tube becomes fatter
in the y direction
P5 : Cross section type
P6 : Cross section rotation angle (degrees)
What does "is related to the number of turns per unit length " exactly mean.

Because I´m trying to wirte .Pov Files out of a Programm, so that i can make
a movie of a moving coil spring.
But i´m not able to calculate the parameter P1 for different lengths of the
coil spring but the same number of windings.
hopefully someone is able to help me, its very urgent!!
I want to use it for a presentation of my final career project
Thanks
Martin alias rossy


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From: Enrico Sanna
Subject: Re: using a helix_1 as a coil or helical spring, what is the Parameter P1 exact=
Date: 13 Jan 2004 17:34:16
Message: <40042C14.90005@tiscali.it>
Hi,

Calculations are quite easy.
P1 tells Povray how many turnings per unit you want. If you, e.g., 
choose to have two turnings on your 3-unit-high helix, and your helix 
iso object is four units high (i.e. along y-axis), you'll have 2 divided 

by 3 rounds per pov-unit.
Let's suppose you're going to trace a helix two units high, and you want 

  it to turn three times around its center. Afterwards, you want that 
same helix to stretch up to three units. What will you do? If you want 
your helix to draw its usual three turnings, you'll have to change P1 
 
which was previously 3/2=1.5  to 3/3=1.
Hope this'll clear out doubts.

Enrico

rossy wrote:
 > Hallo
 >
 > it follows a cut out of the User Manual:
 > f_helix1(x,y,z, P0, P1, P2, P3, P4, P5, P6)
 >
 > P0 : Number of helixes - e.g. 2 for a double helix
 > P1 : Period - is related to the number of turns per unit length
 > P2 : Minor radius (major radius > minor radius)
 > P3 : Major radius
 > P4 : Shape parameter. If this is greater than 1 then the tube becomes 

fatter
 > in the y direction
 > P5 : Cross section type
 > P6 : Cross section rotation angle (degrees)
 > What does "is related to the number of turns per unit length " 
exactly mean.
 >
 > Because I´m trying to wirte .Pov Files out of a Programm, so that i 

can make
 > a movie of a moving coil spring.
 > But i´m not able to calculate the parameter P1 for different lengths
 
of the
 > coil spring but the same number of windings.
 > hopefully someone is able to help me, its very urgent!!
 > I want to use it for a presentation of my final career project
 > Thanks
 > Martin alias rossy
 >
 >
 >
 >


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